Question

Write the atomic number of the element present in the third period and seventeenth group of the periodic table.

Answer 1

Periodic table:

• The periodic table is an arrangement of all the elements known to man in accordance with their increasing atomic number and recurring chemical properties.
• It consists of horizontal rows called Periods. There are a total of $7$periods.
• And vertical columns are called groups. There are a total of $18$ groups.

Identifying the element present in the third period and a seventeenth group of the periodic table:

• The first period of the periodic table has a total of $2$ elements.
• The second period of the periodic table has a total of $8$ elements.
• The third period also consists of $8$ elements.
• The third period begins with the element having an atomic number, $Z=11$.
• In the third period, the first two elements( with $Z=11\&12$) fall in group $1$ and $2$.
• Elements with $Z=13$ Onwards are placed in group $13$ onwards.
• As a result of which, the element with atomic number $Z=17$ is present in group seventeenth and third period of the periodic table.
• The element is Chlorine having atomic number 17.